Figure 3
From: Fast-moving dislocations trigger flash weakening in carbonate-bearing faults during earthquakes
Evolution of the marble microstructures with increasing slip.
Sliding surface after (a) 0 mm, (b) 1.5 mm and (c) 5 mm slip (SEM images). (a) Rare incoherent flat micro-patches induced through diamond tool rock polishing in pre-sheared surfaces. (d) TEM image of a FIB-SEM section across the micro-patch in (a) reveals a nanograin volume (grain size >50 nm) covering bands of interleaving, elongated calcite grains. The remaining sample surface is free of nanograins (Supplementary Fig. S3 online). With increasing displacement flat slip surfaces (b and c) spread coherently across the sample. (e) A nanograin volume (Domain 1) develops below the slip surface covering extensively cleaved (CP: cleavage plane) and fractured calcite grains (Domain 2). The latter terminates into un-deformed calcite grains (Domain 3). Domains 1, 2, 3 are separated by dashed lines. (f) After 5 mm displacement the nanograin volume is covered by a semi-coherent amorphous carbon (a–C) layer.
